Radio installations in aircraft are required to simultaneously process many different radio standards, relating to many different frequency bands and modulation types. FIG. 1 shows a table, listing the main radio bands in present use for civil aviation and the bands proposed for future use, together with the operating frequency ranges for each and the bandwidths in use for each. These radio bands include the HF band at 2-30 MHz, VHF at 118-137 MHz, and various bands above 1 GHz such as those used by the Inmarsat, Thuraya, Iridium and GlobalStar systems. Proposed new bands are the L-band at 960-1024 MHz, and the C-band at 5091-5150 MHz.
Due to the considerable diversity of operating frequency and modulation type, aircraft radio installations typically include multiple types of radio equipment, with each radio standard serviced by dedicated equipment, including duplicates for redundancy. Almost all of the radio equipment is installed at a single location in the aircraft. The result is a significant cost in weight, physical volume, and power consumption.
These factors are driving the industry to adopt software defined radio (SDR) technology as a means to increase the level of integration and functionality while reducing the size and weight of the radio installation. Software Defined Radio (SDR) is a radio communication system where components that have traditionally been implemented in hardware, such as mixers, filters, amplifiers, modulators/demodulators, detectors, etc., are instead implemented using software on a computer.